America's number one. Positive -- is back on the stand in his murder trial this morning following an emotional day in which he apologized to the family of the girlfriend who shot -- -- -- -- -- -- I'm Bradley has the latest. More drama. Expected today in the Oscar the story -- murder trial the paralympic athlete is back on the witness stand to explain the key question why he pulled that trigger. The stories has pleaded not guilty saying he mistook his girlfriend model and reality star -- -- camp for an intruder. Yesterday on the stand as his voice quiver he made this tearful apology to -- camps -- -- -- -- Defendants sort of been into the smoke quotes you Newfoundland. -- camps mother sat expressionless. -- like others in the courtroom. While the stories went on and on about his life story including his difficult last year that I have to Bloomberg News. The defense hopes to present the star known as the blade runner as a man crippled by guilt and depression. An athlete once on top of the world who now lives in deep paranoia of good. The security guard that stands outside -- welfare -- -- months this story as his lawyers are also focused on the double amputees disability. Trying to show that he felt vulnerable the night he shot and killed -- camp. The defense wants to argue that he reasonable person in his position. With his disabilities. Would have more fear than an ordinary person. In the end that judge will decide the story -- fate whether this was a tragic mistake or cold blooded murder. -- Bradley ABC news Washington.

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